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Show 304 IMPERFECTION OF THE CHAP. IX. any secondary £ormation, seemed fully to justify the belief that this great and distinct order had been suddenly produced in the interval be_tween the latest secondary and earliest tertiary formation. But now we may read in the Supplement to Lyell'_s 'Manual,' published in 1858, clear evidence of the existence of whales in the upper greensand, some time before the close of the secondary period. · I may give another instance, which from having passed under my own eyes has much struck me. In a memoir on Fossil Sessile Cirripedes, I have stated that, from the number of existing and extinct tertiary species; from the extraordinary abundance of the individuals of many species all over the world, from the Arctic regions to the equator, inhabiting various zones of depths from the upper tidal limits to 50 fathoms ; from the perfect manner in which specimens are preserved in the oldest tertiary beds ; from the ease with which even a fragment of a valve can be recognised; from all these circumstances, I inferred that had sessile cirri pedes existed during the secondary periods, they would certainly have been preserved and discovered ; and as not one species had been discovered in beds of this age, I concluded that this great group had been suddenly developed at the commencement of the tertiary series. This was a sore trouble to me, adding as I thought one more instance of the abrupt appearance of a great group of species. But my work had hardly been published, w~en a skilful palreontologist, M. Bosquet, sent me a drawing of a perfect specimen of an unmistakeable sessile cirripede, which he had himself extracted from t~e .chalk of Belgium. And, as if to make the case as striking as possible, this sessile cirripede was a Chthamalus, a very common, large, and ubiquitous genus, of which not _one specimen has as yet been found even in any tertJary CHAP. IX. GEOLOGICAL RECORD. 305 stratum. Hence we now positively know that sessile cirri pedes existed during the secondary period; and these cirripedes might have been the progenitors of our many tertiary and existing species. The case most frequently insisted on by palreontologists of the apparently sudden appearance of a whole group of species, is that of the teleostean fishes, low down in the Chalk period. This group includes the large majority of existing species. Lately, Professor Pictet has carried their existence one sub-stage further back ;· and some palreontologists believe that certain much older fishes, of which the affinities are as yet imperfectly known, are really teleostean. Assuming, however, that the whole of them did appear, as Agassiz believes, at the commencement of the chalk formation, the fact would certainly be highly remarkable; but I cannot see that it would be an insuperable difficulty on my theory, unless it could likewise be shown that the species of this group appeared suddenly and simultaneously throughout the world at this same period. It is almost superfluous to remark that hardly any fossilfish are known from south of the equator ; and by running through Pictet' s Palreontology it will be seen that very few species are known from several formations in Europe. Some few families of fish now have a confined range; the teleostean fish might formerly have had a similarly confined range, and after having been largely developed in some one sea, might have spread widely. Nor have we any right to suppose that ~he seas of the .world have always been so freely open from south to north as they are at present. Even at this day, if the Malay Archipelago were converted into land, the tropical parts of the Indian Ocean would form a large and perfectly enclosed basin, in which any great group of marine animals might be multiplied ; and |